The number of adults affected by asthma in the United States has grown dramatically in the past two decades and asthma now affects 14 million adults. Control of asthma is inadequate for many of them, leading to substantial morbidity and economic burden. The primary goal of our proposal is to develop and assess the value of a home-based education and support intervention called HomeBASE (Home-Based Asthma Support and Education) for reducing asthma morbidity among low-income, ethnically diverse adults with asthma ages 18-65. The value of an in-home intervention, while effective among children with asthma and theoretically appealing, has not been assessed among adults. Specifically, the project will test the hypothesis that community health workers providing education and support for self-management of asthma, assessment of the home for environmental triggers, resources for asthma control, and assistance in effective communication with medical providers over the course of one year will reduce asthma morbidity, asthma- related urgent health care use and exposure to indoor asthma triggers. A randomized controlled trial using participatory research methods will be used. Four hundred twenty participants will be enrolled and followed for two years. Primary outcomes include asthma symptom-free days, asthma-related quality of life and urgent health service use. Full data will be collected in person at baseline, and one and two years later. Interim data will be obtained through telephone interviews. Exposure to asthma triggers will be assessed through interviews, home inspection and analysis of house dust for mite allergen. The incremental cost- effectiveness (dollars per symptom-free day) will be measured. Other aims include (1) ensuring community participation in study design, implementation, evaluation and dissemination and (2) and disseminating protocols and tools for program replication should HomeBASE prove successful. The proposal was initiated by and is sponsored by the King County Asthma Forum, the local asthma coalition. It has been developed through existing collaborative relationships among partners who are members of the HomeBASE Steering Committee: people with asthma, private sector clinics and hospitals, community clinics, the local public hospital, the local health department, community-based organizations and the University of Washington. The Community Advisory Group, consisting of people with asthma, has advised on proposal development.